Is CVE-2011-0539 in the CISA KEV catalog?

No. CVE-2011-0539 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2011-0539?

CVE-2011-0539 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2011-0539?

CVE-2011-0539 has an EPSS score of 1.80% (76th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2011-0539?

Upgrade openssh on debian 11 to 1:5.8p1-2 or later.

CVE & CISA-KEV Catalog

CVE-2011-0539

HIGHEPSS 76th pctl

7.5

CVSS v3

NVD

Description

The key_certify function in usr.bin/ssh/key.c in OpenSSH 5.6 and 5.7, when generating legacy certificates using the -t command-line option in ssh-keygen, does not initialize the nonce field, which might allow remote attackers to obtain sensitive stack memory contents or make it easier to conduct hash collision attacks.

CWE-264Permissions, Privileges, and Access Controls CWE-457

How to fix

Remediation Available

opensshDebian

Fixed in:1:5.8p1-2CVE-2011-0539

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploit Intelligence

1.80%probability of exploitation in 30 days

76thpercentile

Elevated risk: more likely to be exploited than 76% of all known CVEs.

References

Patch1

openssh.com

Vendor Advisory2

Other references7

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-29.